package com.eve.eplus.common.task;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Collections;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.widget.ImageView;

import com.eve.eplus.common.tools.LogTools;

public class ImageLoader
{
    private MemoryCache memoryCache = new MemoryCache();
    private AbstractFileCache fileCache;
    private Map<ImageView, String> imageViews = Collections.synchronizedMap(new WeakHashMap<ImageView, String>());// 线程池
    private ExecutorService executorService;

    public ImageLoader(Context context)
    {
        fileCache = new AbstractFileCache(context);
        executorService = Executors.newFixedThreadPool(5);
    }

    // 最主要的方法
    public void DisplayImage(String url, ImageView imageView,
            boolean isLoadOnlyFromCache)
    {
        imageViews.put(imageView, url);
        if (!isLoadOnlyFromCache) {
        // 先从内存缓存中查找
        Bitmap bitmap = memoryCache.get(url);
        if (bitmap != null)
            imageView.setImageBitmap(bitmap);
        else 
        {

            // 若没有的话则开启新线程加载图片
            queuePhoto(url, imageView);
        }
        }
    }

    private void queuePhoto(String url, ImageView imageView)
    {
        PhotoToLoad p = new PhotoToLoad(url, imageView);
        executorService.submit(new PhotosLoader(p));
    }

    private Bitmap getBitmap(String url)
    {
        File f = fileCache.getFile(url);

        // 先从文件缓存中查找是否有
        Bitmap b = null;
        if (f != null && f.exists())
        {
            b = decodeFile(f);
        }
        if (b != null)
        {
            return b;
        }
        // 最后从指定的url中下载图片
        try
        {
            Bitmap bitmap = null;
            URL imageUrl = new URL(url);
            HttpURLConnection conn = (HttpURLConnection) imageUrl.openConnection();
            conn.setConnectTimeout(30000);
            conn.setReadTimeout(30000);
            conn.setInstanceFollowRedirects(true);
            InputStream is = conn.getInputStream();
            OutputStream os = new FileOutputStream(f);
            CopyStream(is, os);
            os.close();
            bitmap = decodeFile(f);
            return bitmap;
        }
        catch (Exception ex)
        {
            LogTools.error("getBitmap catch Exception...\nmessage = "
                    + ex.getMessage());
            return null;
        }
    }

    // decode这个图片并且按比例缩放以减少内存消耗，虚拟机对每张图片的缓存大小也是有限制的
    private Bitmap decodeFile(File f)
    {
        try
        {
            // decode image size
            BitmapFactory.Options o = new BitmapFactory.Options();
            o.inJustDecodeBounds = true;
            BitmapFactory.decodeStream(new FileInputStream(f), null, o);

            Bitmap bitmap;
            // Find the correct scale value. It should be the power of 2.
            final int REQUIRED_SIZE = 200;
            int width_tmp = o.outWidth, height_tmp = o.outHeight;
            int scale = 1;
            while (true)
            {
                if (width_tmp / 2 < REQUIRED_SIZE
                        || height_tmp / 2 < REQUIRED_SIZE)
                    break;
                width_tmp /= 2;
                height_tmp /= 2;
                scale *= 2;
            }

            // decode with inSampleSize
            BitmapFactory.Options o2 = new BitmapFactory.Options();
            o2.inSampleSize = scale;
            //对超长的图片进行处理
            if(width_tmp>1000)
                bitmap = Bitmap.createBitmap(BitmapFactory.decodeStream(new FileInputStream(f), null, o2), 0, 0, width_tmp/10, height_tmp);
            else if(height_tmp>1000)
                bitmap = Bitmap.createBitmap(BitmapFactory.decodeStream(new FileInputStream(f), null, o2), 0, 0, width_tmp, height_tmp/10);
            else
            bitmap= BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
            return bitmap;
        }
        catch (FileNotFoundException e)
        {

        }
        return null;
    }

    // Task for the queue
    private class PhotoToLoad
    {
        public String url;
        public ImageView imageView;

        public PhotoToLoad(String u, ImageView i)
        {
            url = u;
            imageView = i;
        }
    }

    class PhotosLoader implements Runnable
    {
        PhotoToLoad photoToLoad;

        PhotosLoader(PhotoToLoad photoToLoad)
        {
            this.photoToLoad = photoToLoad;
        }

        @Override
        public void run()
        {
            if (imageViewReused(photoToLoad))
                return;
            Bitmap bmp = getBitmap(photoToLoad.url);
            memoryCache.put(photoToLoad.url, bmp);
            if (imageViewReused(photoToLoad))
                return;
            BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad);
            // 更新的操作放在UI线程中
            Activity a = (Activity) photoToLoad.imageView.getContext();
            a.runOnUiThread(bd);
        }
    }

    /**
     * * 防止图片错位
     * *
     * * @param photoToLoad
     * * @return
     * */
    boolean imageViewReused(PhotoToLoad photoToLoad)
    {
        String tag = imageViews.get(photoToLoad.imageView);
        if (tag == null || !tag.equals(photoToLoad.url))
            return true;
        return false;
    }

    // 用于在UI线程中更新界面
    class BitmapDisplayer implements Runnable
    {
        Bitmap bitmap;
        PhotoToLoad photoToLoad;

        public BitmapDisplayer(Bitmap b, PhotoToLoad p)
        {
            bitmap = b;
            photoToLoad = p;
        }

        public void run()
        {
            if (imageViewReused(photoToLoad))
                return;
            if (bitmap != null)

                photoToLoad.imageView.setImageBitmap(bitmap);
        }
    }

    public void clearCache()
    {
        memoryCache.clear();
        fileCache.clear();
    }

    public static void CopyStream(InputStream is, OutputStream os)
    {
        final int buffer_size = 1024;
        try
        {
            byte[] bytes = new byte[buffer_size];
            for (;;)
            {
                int count = is.read(bytes, 0, buffer_size);
                if (count == -1)
                    break;
                os.write(bytes, 0, count);
            }
        }
        catch (Exception ex)
        {
            LogTools.error("CopyStream catch Exception...");
        }
    }
}
